The invention relates to the production of cream cheese. More specifically, the invention relates to methods for producing a wheyless cream cheese using transglutaminase.
Cheese compositions are generally prepared from dairy liquids by processes that include treating the liquid with a coagulating or clotting agent. The coagulating agent may be a curding enzyme, an acid, or a suitable bacterial culture. The coagulum or curd that results generally incorporates transformed casein, fats (including natural butter fat), and flavorings (especially those arising when bacterial cultures are used). The curd is usually separated from the whey and is then collected. The resulting liquid whey generally contains substantial portions of nutrients, including soluble proteins, mineral salts, and lactose, that are normally lost in the manufacturing process. The inability of whey nutrients to be retained in the coagulum is an important factor contributing to a lack of efficiency in production of cheese curds, and to a reduction in overall yield of protein solids from the starting dairy liquids. Therefore, there remains a need for more effective methods of improving the efficiency of nutrient incorporation during cheese production.
Cream cheese is a mild, acid-coagulated uncured cheese made of dairy components including a fat source (e.g., a mixture of cream and milk). Cream cheese is normally stored under refrigeration conditions (i.e., about 2 to about 8xc2x0 C.) and typically has a smooth and butterlike body. At refrigeration temperatures, cream cheese can normally be sliced, but it is not soft or readily spreadable and cannot readily be applied to a soft or brittle substrate.
Attempts have been made to develop a process for making wheyless cream cheese in which nutrients traditionally lost in the whey are retained in the cheese product. However, cheese or cheese-like products produced by such processes typically do not have the body, texture, and/or taste desired in cream cheese. Therefore, there remains a need to develop processes for making cream cheese in which the cheese has body, texture, and taste similar to that found in cream cheese prepared by conventional processes (i.e., curds and whey processes).
U.S. Pat. No. 5,882,704 discloses a process for the production of cream cheese-like products in which whey is not removed during the process. The methods disclosed do not include the use of transglutaminase to improve the texture and body of the wheyless cheese produced. Furthermore, the method disclosed uses an emulsifier which adds cost to the process. Moreover, under the current United States Standards of Identity, a product containing such emulsifiers cannot be labeled as cream cheese.
U.S. Pat. No. 4,724,152 discloses a process for the production of cream cheese-like products in which whey is not removed during the process. The methods disclosed in this patent do not include the use of transglutaminase to improve the texture and body of the wheyless cheese produced. Furthermore, the methods disclosed uses stabilizers which increases the cost of processing using the disclosed method. Moreover, in some countries, a product containing stabilizers cannot be labeled as cream cheese; in the United States, the Standards of Identity limit the total amount of stabilizers to less than 0.5 percent for cream cheese.
In addition to inefficiencies in nutrient utilization during production, cream cheeses also lose nutrients during storage as a result of syneresis (i.e., water separation). Acid whey generated by syneresis, although it contains substantial amounts of dairy proteins, cannot be efficiently utilized. Moreover, consumers generally consider syneresis to be a product defect. Therefore, there remains a need for improved methods for producing cream cheeses wherein syneresis is reduced.
Transglutaminases are enzymes which catalyze the cross-linking of proteins. These enzymes have a broad occurrence in nature and may be obtained, for example, from microorganisms such as those belonging to the genus Streptoverticillium or from Bacillus subtilis, from various Actinomycetes and Myxomycetes, from fish and other marine sources, from plant sources, and from animal sources (especially mammals).
Food processing methods employing transglutaminase have been disclosed in recent years. For example, Japanese Patent 59059151 discloses treating an emulsion containing proteins, oils or fats, and water with transglutaminase to produce a gelatinous, cross-linked gel. However, the cross-linked gel does not have the texture, body, and/or taste of cream cheese. Japanese Patent 02276541 discloses a heat-resistant food protein having a fiber texture prepared by treatment of a protein hydrogel with a transglutaminase in the presence of calcium ions to induce cross-linking of the surfaces of fiber bundles. However, the heat resistant food protein does not have the texture, body, and/or taste of cream cheese.
U.S. Pat. No. 5,156,956 discloses a transglutaminase purified from strains of the genus Streptoverticillium, and the use of this enzyme to produce gel type foods. This transglutaminase catalyzes formation of protein gelation products from protein solutions to produce conventional gel foodstuffs such as yogurt, jelly, cheese, gel cosmetics, and the like. No methods are disclosed in this patent for using transglutaminase to produce cream cheese or to use transglutaminase to produce cheese without forming a gel. Furthermore, methods are not disclosed in this patent for both acidifying a dairy liquid and cross-linking proteins in the dairy liquid.
U.S. Pat. No. 5,731,183 discloses a transglutaminase purified from strains of Bacillus subtilis, having particular physical and enzymatic characteristics, and a method for producing protein, peptide, or non-protein amino acid polymers that are cross-linked via their glutamine and lysine residues to form intermolecular or intramolecular conjugates. Although transglutaminase is disclosed as being used in cross-linking protein polymers for use in a variety of food substances, no methods are disclosed for using transglutaminase to produce cheese.
Methods have been proposed for increasing the recovery of whey protein into cheese products using transglutaminase. For example, U.S. Pat. No. 6,093,424 relates to treatment of a dairy liquid such as milk with transglutaminase and a non-rennet protease to generate cheese curd for hard, soft, or semi-soft cheeses. The disclosed methods do not use transglutaminase to produce wheyless cheese; nor do the methods use an acidifying agent, such as a lactic acid producing culture, for making a cheese.
U.S. Pat. No. 5,681,598 and its European counterpart EP 0 711 504 A1 disclose a process for producing cheese using transglutaminase added to milk at a concentration of at least one international unit (IU) transglutaminase per gram milk protein. The transglutaminase is added at the same time as a clotting enzyme and a lactic-acid producing culture; the milk is then incubated. This patent does not disclose a process for using transglutaminase for producing wheyless cheese. Patent publication WO 97/01961 discloses a method for producing cheese using transglutaminase. Transglutaminase is added to milk, followed by a short incubation period, after which a clotting enzyme or curding agent is added to the milk to produce curd. WO 97/01961 does not disclose the use of transglutaminase to produce wheyless cheese.
The current invention meets longstanding needs in the art discussed above. For example, the current invention meets the important need of a process for producing cream cheese in which whey nutrients are not lost in the process. Furthermore, the current invention meets the need of providing a process for preparing wheyless cheese having the texture, body, and taste of conventional cream cheese. Finally, the current invention meets the need of a cream cheese product with significantly reduced syneresis.
The current invention includes a process for making cream cheese wherein nutrients typically lost as whey during processing are utilized in the final cream cheese; the resulting cream cheese has the body, texture, and taste of conventional cream cheese. The process of the current invention utilizes acidifying and cross-linking steps to process a dairy liquid into a wheyless cream cheese by utilizing the protein cross-linking activity of transglutaminase. The wheyless cream cheese does not require the addition of stabilizers and/or emulsifiers. Furthermore, the cream cheese that is formed is firmer than typical cream cheese and has significantly reduced syneresis.
The current invention provides a process for making a wheyless cream cheese, said process comprising:
(1) treating a dairy liquid containing dairy proteins with transglutaminase and a lactic acid producing culture at about 20 to about 40xc2x0 C. (preferably at about 25 to about 40xc2x0 C.) until the pH reaches about 4.2 to about 5.2 to cross-link at least a portion of the dairy proteins and to form a first dairy mixture;
(2) homogenizing the first dairy mixture to break up any curd that may have formed and to form a treated dairy mixture;
(3) cooking the treated dairy mixture at about 75 to about 90xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to about 60 minutes) to form a first blend; and
(4) homogenizing the first blend to form a cream cheese having fat globules with an average diameter of about 0.2 to about 3 microns.
The current invention provides a process for making a wheyless cream cheese, said process comprising:
(1) treating a dairy liquid with transglutaminase at about 40 to about 60xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to 60 minutes) to cross-link at least a portion of the dairy proteins and to form a treated dairy liquid;
(2) cooking the treated dairy mixture at 75 to about 90xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to about 60 minutes) to form a first blend;
(3) adjusting the pH of the first blend to about 4.2 to about 5.2 by adding an edible acid; and
(4) homogenizing the pH-adjusted first blend to form the wheyless cream cheese having fat globules with an average diameter of about 0.2 to about 3 microns.
The current invention also provides a process for making a wheyless cream cheese, said process comprising:
(1) blending a dairy liquid containing dairy proteins with transglutaminase and a lactic acid producing culture to form a first dairy mixture;
(2) incubating the first dairy mixture at about 20 to about 40xc2x0 C. (preferably at about 25 to about 40xc2x0 C.) until the pH reaches about 4.2 to about 5.2 to cross-link at least a portion of the dairy proteins and to form a second dairy mixture;
(3) homogenizing the second dairy mixture to break up any curd that may have formed and to form a third dairy mixture;
(4) heating the third dairy mixture at about 40 to about 60xc2x0 C. for about 2 to about 60 minutes to form a treated dairy liquid;
(5) mixing the treated dairy liquid with a wet mix or a treated wet mix to form a first blend;
(6) homogenizing the first blend to form a second blend;
(7) cooking the second blend at a temperature of about 75 to about 90xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to about 60 minutes) to form a third blend; and
(8) homogenizing the third blend to form a cream cheese having fat globules with an average diameter of about 0.2 to about 3 microns;
wherein the wet mix is prepared by a first method comprising:
(A) blending whey protein, milk protein concentrate, or mixtures thereof in water at a temperature of about 60 to about 75xc2x0 C. to form a first mixture containing dairy proteins; and
(B) blending fat with the first mixture to form the wet mix; and
wherein the treated wet mix is prepared by a second method comprising:
(A) homogenizing the wet mix;
(B) adding transglutaminase to the homogenized wet mix to form a second mixture; and
(C) incubating the second dairy mixture for a time and temperature sufficient to cross-link at least a portion of the dairy proteins to form the treated wet mix.
The current invention also provides a process for making a wheyless cream cheese, said process comprising:
(1) blending a dairy liquid containing dairy proteins with transglutaminase to form a first dairy mixture;
(2) incubating the first dairy mixture at about 40 to about 60xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to 60 minutes) to cross-link at least a portion of the dairy proteins to form a treated dairy liquid;
(3) mixing the treated dairy liquid with a wet mix or a treated wet mix to form a first blend;
(4) homogenizing the first blend;
(5) cooking the homogenized first blend at about 50 to about 95xc2x0 C. for about 2 to about 120 minutes (preferably about 10 to about 60 minutes) to form a second blend;
(5) adjusting the pH of the second blend to about 4.2 to about 5.2 by adding an edible acid to form a third blend; and
(6) homogenizing the third blend to form a cream cheese having fat globules with an average diameter of about 0.2 to about 3 microns;
wherein the wet mix is prepared by a first method comprising:
(A) blending whey protein, milk protein concentrate, or mixtures thereof in water at a temperature of about 60 to about 75xc2x0 C. to form a first mixture containing dairy proteins; and
(B) blending fat with the first mixture to form the wet mix; and
wherein the treated wet mix is prepared by a second method comprising:
(A) homogenizing the wet mix;
(B) adding transglutaminase to the homogenized wet mix to form a second mixture; and
(C) incubating the second dairy mixture for a time and temperature sufficient to cross-link at least a portion of the dairy proteins to form the treated wet mix.